In recent years, a capsule endoscope having an imaging function and a radio communication function has appeared in the field of an endoscope. This capsule endoscope has a configuration that is swallowed by a subject from the mouth to perform an observation (examination), moves within the internal organs (within the body cavity) such as the stomach and the small intestine, along a peristatic motion, and sequentially images using the imaging function, until when the capsule endoscope is naturally discharged from the body (human body).
During this observation period while the capsule endoscope is moving within the internal organs, image data acquired within the body cavity by the capsule endoscope is sequentially transmitted to the outside of the subject by the radio communication function, and is stored into a memory provided within a receiving apparatus at the outside. Because the subject carries the receiving apparatus having the radio communication function and the memory function, the subject can move freely even during the observation period after swallowing the capsule endoscope until when the capsule endoscope is discharged. After the observation, a doctor or a nurse can perform diagnosis by displaying the images of the body cavity onto a display unit such as a display, based on the image data stored in the memory of the receiving apparatus (for example, see Patent Document 1).
According to a conventional capsule endoscope, image data picked up by the capsule endoscope is radio transmitted in a data configuration similar to that of an image transfer according to an NTSC system, for example. In other words, a conventional capsule endoscope system transmits synchronization data including a vertical synchronization signal synchronized in a vertical direction and each scan line data including a horizontal synchronization data, in a state that what is called a horizontal blanking period is provided between scan line data, using image data corresponding to one image as one unit.
Patent Document 1: Japanese Patent Application Laid-open No. 2001-231186 (Page 3, FIG. 1)